Fluid pressure brake



E. E. HEWITT 2,147,299

FLUID PRESSURE BRAKE Filed Aug. 24, 1935 2 Sheets-Sheet l Tu W RMM/Y m m ma k W a 7? L E mdikl m Feb. 14, 1939.

Feb. 14, 1933. E E, HEW|TT 2,147,299

FLUID PRESSURE BRAKE Filed Aug. 24, 1935 2 Sheets-Sheet 2 Fig.3

INVENTOR ELLIS E. HEWITT. BY

ATTORNEY Patented Feb. 14, 1939 UNiTED STATES PATENT OFFICE FLUID PRESSURE BRAKE Application August 24,

Claims.

This invention relates to electropneumatic brakes and more particularly to a braking system in which the brakes may be controlled both electrically and pneumatically.

Braking systems have heretofore been developed which employ a brake pipe to supply fluid under pressure'to reservoirs from which fluid is supplied to the vehicle brake cylinders to effect an application of the brakes, and in these systems the supply of fluid under pressure to the brake cylinders from the reservoirs, and the release of fluid under pressure from the brake cylinders is controlled by means of relay valve devices carried on each of the cars of the train,

and which are controlled by variations in the pressure of the fluid in a control pipe.

In these systems the pressure of the fluid in the control pipe may be controlled by means of an engineers brake valve which controls the supply and release of fluid under pressure to and from the control pipe, either directly or through a relay valve, together with electrically operated means which controls the supply of fluid to the control pipe from reservoirs on the cars, and the release of fluid under pressure from the control pipe through magnet valves mounted on the cars.

There is a possibility that in the event of a disturbance of the wires leading to the magnet valves, that the windings of both the application and release magnet valves employed in these systems will be energized at the same time, which would result in the release of fluid from the control pipe, and the loss of fluid in the reservoirs from which fluid is supplied in effecting an application of the brakes, with the result that no fluid would be available to eiiect a brake application.

There is a possibility also that in the event of a .a rupture of the control pipe, such as might be caused by a break in two of the. train, the electrically operated means for supplying fluid to the control pipe will continue to supply fluid to the control pipe from the supply reservoirs until the fluid in these reservoirs is exhausted.

It is the principal object of the present invention to provide a braking system of the type described and incorporating means responsive to the pressure of the fluid in the brake pipe and controlling the electrically operated means for supplying fluid to the control pipe so as to cut off the supply of fluid by this means from the supply reservoirs on a reduction in the pressure of the fluid in the brake pipe.

5 Other objects of the invention and features of 1935, Serial No. 37,701

(Cl. 303-l.5)

novelty will be apparent from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a diagrammatic view, largely in section, of one form of braking system embodying my invention;

Fig. 2 is a diagrammatic development of the manual control means employed in the system shown in Fig. 1; and

Fig. 3 is a fragmentary diagrammatic View of a modified form of braking system embodying my invention.

Referring to Fig. l of the drawings, the system therein illustrated includes an engineers brake valve I, a conductors brake valve 2, a fluid pressure operated valve device. 3, a main reservoir 4, a relay valve 5, a fluid pressure operated switch device l, a relay valve device 9, an application magnet valve device I I, a release magnet valve device I2, a brake cylinder I4, a supply reservoir I5, a fluid pressure operated valve device I6, a control pipe IT, a brake pipe. I8, and a control reservoir I9.

The engineers brake valve I comprises a body having a rotary valve seat 30 therein, the valve seat having a port 3! communicating with the brake pipe I8, an atmospheric exhaust port 33, and a port 35 which communicates with a pipe 36 which leads to the fluid pressure operated valve device 3.

The engineers brake valve I has a rotary valve 31 mounted in a chamber therein, the rotary valve having ports formed therein adapted in different positions of the rotary valve, as will hereinafter more fully appear, to establish communication between the chamber 39 above the rotary valve, and which is constantly connected to the main reservoir 4 by way of a passage. pipe 49, and the brake pipe I8, and the pipe St, or between the pipe 36, or the brake pipe l8 and the atmospheric exhaust port 33. The rotary valve 31 is adapted to be operated between its different positions by means of the manual operating handle 42.

The conductors brake valve 2 comprises a casing indicated generally by the reference numeral and having a chamber 46 therein which is constantly connected to the brake pipe I 8 by way of a pipe 48. The valve element 50 is mounted in the chamber it, and is normally urged into engagement with a seat rib 5i by means of a spring 52 so as to cut off communication between the chamber M5 and the atmosphere by way of the passage 53. The valve 50 has a stem 55 which is adapted to be engaged by a lever 51 which is operated by means of a lever 58 having a cam surface 59 formed thereon and engageable with the lever 51.

When the lever 58 is rotated the cam surface 59 engages the lever 51 so as to move the lever 51 downwardly, and it presses on the stem 55 so as to move the valve 50 away from the seat 5I, and thereby establish communication between the chamber 46 and the atmosphere by way of the passage 53.

The fluid pressure operated valve device 3 comprises a casing having a bore therein in which is mounted a piston 65 having a chamber 66 at one side thereof connected to the brake pipe I8 by way of a pipe 69.

The piston 65 has on the opposite side thereof a valve chamber 10 which is constantly connected to the main reservoir 4 by way of a pipe I2. A slide valve 14 is positioned in the valve cham'- ber 18 and is slidable upon a seat 15, and has a cavity 11 formed therein which controls communication between a port 19 and the port 89 in the slide valve seat 15. The port 19 has connected thereto the pipe 36 leading from the engineers brake valve I, and the port 88 is connected by way of the pipe 82 with a passage in the relay valve device 5. The body of the fluid pressure operated valve device 3 also has a passage 84 formed therein which has a restricted portion 86- interposed therein. The passage 84 communicates with a port in the valve seat and is adapted to be uncovered by the end of the slide valve 14 in one position of the slide valve.

Ihe slide valve 14 is operated by means of a stem 81 associated with the piston 65, while the piston 65 is normally urged to the right, as viewed in the drawings, by means of a spring 88.

The relay valve device 5 comprises a body indicated generally by the reference numeral 98, and having a bore therein in which is located the piston 92 having on one side thereof a chamber 93 which is connected through a restricted passage 94 with a passage 95 to which is connected the pipe 82.

The piston 92 has on the other side thereof a valve chamber 98, in which is mounted a slide valve I09, and which is slidable upon a seat IDI formed in the body 90, and this seat has a pair of ports I82 and I93 formed therein and communicating with the atmosphere. The slide valve I96 is adapted to be operated by a stem I86, which is formed integral with the piston 92, While the slide valve I88 has a port I91 extending therethrough and adapted in one position on the slide valve I99 to be substantially in alignment with the port I82 in the slide valve seat IUI.

The body 98 in addition has a valve chamber H8 formed therein in which is mounted a valve III, which is normally urged into engagement with a seat rib II2 by means of a spring H5. The valve III has associated therewith a member II6 which is adapted to be engaged by the end of the stem I66.

The valve III also has associated therewith a pilot valve device comprising a valve element I28 which is normally urged by means of a spring I24 into engagement with a seat rib I22 formed on the member H6. The valve element I29 has a stem I25 associated therewith and positioned in a bore in the member H6 and the stem I25 projects from the face of the member H6 so as to be engaged by the end of the stem I96 before the member H6 is engaged thereby.

The valve chamber H8 is constantly connected with the main reservoir 4 by way of a pipe and passage I39, while the valve chamber 98 is constantly connected with the control pipe I1 by way of a passage I32.

The relay valve device 5 has a pair of check. valve devices associated therewith and indicated generally by the reference numerals I36 and I31. The check valve device I36 is adapted to permit flow from the passage 95 in the body 98 to the passage I32, and to prevent flow from passage 2' 32 to the passage 95, while the check valve device I31 is adapted to permit flow from the passage I32 to the passage 95, and to prevent flow from the passage 95 to the passage I32.

The check valve device I36 comprises a chamber I49, in which is mounted a valve element I42, which is urged by a spring I41 into engagement with a seat rib I44 surrounding a passage I45 which communicates with the passage 95. On a predetermined increase in the pressure of the fluid in the passage 95 over that in the passage I 3'2 the valve element I42 will be lifted off from the seat rib I44 by the pressure of the fluid in the passage I45 acting on the face of the valve I42 within the seat rib I44, and fluid will thereupon flow from the passage 95 to the chamber I49 and therefrom by way of the passage I48 to the passage I32.

The check valve device I31 is similar in construction to the check valve device I36, and comprises a chamber I59, in which is mounted a valve element I5I, which is normally urged by a spring I55 into engagement with a seat rib E52 surrounding a passage I53 leading to the passage I32. The chamber I58 is connected to the passage 95 by way of a passage I56, and on an increase in the pressure of the fluid in the passage I32, the fluid in the passage I53 acting on the face of the valve I5I within the seat rib I 52 will cause the valve element I5I to be moved away from the seat rib I52 so as to permit fluid to flow from the passage I32 to the chamber I50, and therefrom by way of the passage I56 to the passage 95.

The relay valve device 5 has associated therewith the fluid pressure operated switch device 1, which as shown, comprises a pair of housing sections I38 and NH which have clamped therebetween the diaphragmi63, which has on one side thereof a chamber I65 which is constantly connected to the passage 95 by Way of a passage I81, and. which has on the other side thereof a chamber I68 which is constantly connected to the control pipe I1 by way of passage I69.

The diaphragm I63 has operatively connected thereto a stem I16, which is connected by means of wires I12 to one side of a source of current, such as the battery I13, the other side of which is connected to ground.

The housing section IBI of the fluid pressure operated switch device 1 has mounted thereon adjacent the end of the stem I19 a contact I15 which is connected by means of a wire I11 with the winding of the release magnet Valve device I2.

The housing section I69 of the fluid pressure operated switch device 1 has mounted thereon a contact I18 which is connected by way of a wire I19 with the winding of the application magnet valve device II.

The stem I19 is adapted in one position of the diaphragm I63 to engage the contact I15 to complete a circuit through said contact from the battery I13, and in another position of the diaphragm I63 to engage the contact I18 and establish a circuit through this contact from the battery I13.

The diaphragm I63 is constructed so as to normally maintain the stem IIIl in engagement with the contact 275, and thus maintain a circuit through the winding of the release magnet valve device I2.

The relay valve device 9 comprises a body I having a bore therein in which is mounted a piston Itii having a chamber I88 on one side thereof which is constantly connected with the control pipe H by way of a passage I89.

The piston 585 has on the opposite side thereof a slide valve chamber I9I, in which is mounted a slide valve H52, which is adapted to be operated by means of a stem I94 associated with the piston 86, and which controls communication between the slide valve chamber I9! and the atmosphere by way of a passage I95.

The body I55, in addition, has a valve chamber it? formed therein in which is mounted a valve element 599, which is normally urged into engagement with a seat rib 2M by means of a spring 262 so as to out off communication between the valve chamber Hi? and the slide valve chamber 5:35. The valve element it has a member 2M associated therewith and adapted to be engaged by the end of the stem I 94.

The valve I99, in addition, has associated therewith pilot valve comprising a valve element 295, which is normally urged into engagement with a seat rib 258 on the member 2% by means of a sprin 289, and which has associated therewith a stem 2! 2 positioned in a bore extending th ough the member 29 2 the stem 2H2 projecting from the face of the member 204 so as to be engaged by the end of the piston stem I94 before the member 29% is engaged thereby.

The valve chamber i9! is constantly connected with the supply reservoir its by way of a passage and pipe 255, while the valve chamber I9I is constantly connected to the brake cylinder It by way of a passage and pipe 2E5.

The relay valve device 9 has associated therewith a check valve device indicated generally by the r ference numeral 229 and comprising a chamber which is constantly connected with the supply reservoir 55 by way of a passage 223 and the passage and pipe 255, and this chamber has positioned therein a valve element 225, which is normally urged into engagement with a seat rib 22? by means of a spring 229, while the area within the seat rib 2277 is constantly connected to the brake pipe I? by way of a passage 235.

The application magnet valve ii comprises a casing havin a chamber 25:) therein, in which is mounted a valve element 252, which is normally urged into en agement with a seat rib 253 by means of a spring 2255 and by the pressure of the fluid in a chamber 25? on the upper side of the valve element 252.

The valve element 252 is urged away from the seat rib 2&3 by the pressure of the fluid in the chamber 25% acting on the face of the valve element outwardly of the seat rib 253. The valve element 252 controls communication between the chamber which is connected to the reservoirs I5 and I?! by way of the passage and pipe 258, and a chamber 266, which is constantly connected to the control pipe I? and. the chamber i553 of the relay valve device 9 by way of the passage which has interposed therein a restricted port The application magnet valve device II also includes a casing section having a chamber 265 formed therein in which is mounted a double beat valve element 266, which controls communication between the chamber 265, and a chamber 268, and a chamber 269. The chamber 258 is constantly connected to, the atmosphere, while the chamber 269 is constantly connected to the chamber 258 by way of a passage 2'. The chamber 265 is constantly connected to the chamber 25? on the upper side of the valve element 262 by means of a passage 273. The valve element 255 is normally held in engagement with its upper seat by means of a spring 215, so as to cut off communication between the chamber 2255 and the chamber 288, and is urged downwardly against the spring to its lower seated position by the winding of the magnet valve device on energization thereof so as to cut ofr communication between the chamber 265 and the chamber 269, and permit communication between the chamber 2% and the chamber 268.

The release magnet valve device I2 comprises a casing having a chamber 2% therein which communicates by way of a passage 28I with the passage 25I which communicates with the control pipe I? and with the chamber I88 in the relay valve device 9. The chamber 28% has mounted therein a valve element 282 which is normally held in engagement with a seat rib 28% by means of a spring 285, and by the pressure of the fluid in a chamber 287 on the upper side of the valve element 282.

The valve element 282 controls communication between the chamber 23d and thereby the control pipe I l, and a chamber 2% which is constantly connected to the atmosphere by way of a passage 292 having a restricted portion or choke 293 interposed therein.

The release magnet valve device I2 also includes a casing section having a chamber 2% formed therein in which is mounted a double beat valve element 2%. The chamber 2555 is in constant communication with the chamber 2%? on the upper side of the valve element 282 by means of a passage 298, while the valve 2% is adapted to control communication between the chamber 295 and a chamber 29%, which is constantly connected with the chamber 28% by way of a passage 3%, and a chamber 393 which is constantly connected to the atmosphere.

The double beat valve element 296 is urged to its upper seated position by means of a spring 305 so as to cut ofi communication between the chamber 2% and the chamber 393, and is moved to its lower seated position, as shown in the drawings, on energization of the winding of the magnet valve device so as to cut off communication between the chamber 295 and the chamber 299, and to permit communication between the chamber 295 and the chamber 3&3.

The fluid pressure operated valve device It comprises a casing 32d having a bore therein in which is mounted a piston 322, having on one side thereof a chamber tea. which is constantly connected to the brake pipe is by way of a pipe 325.

The piston 322 has on the other side thereof a valve chamber 328, in which is mounted a slide valve 338, which is slidable upon a seat 33! formed on the casing 326 and which is adapted to be operated by means of a stem 333 associated with the piston 322.

The slide valve seat 33I has a port 335 formed therein and adapted to be uncovered by the slide valve 33.0: in one positionthereof. The port 33.5,

has the pipe 258 leading to the application magnet valve device 1 connected thereto. The valve chamber 328 is constantly connected to the supply reservoir I5 by way of a pipe 338, while the piston 322 is normally held by means of a spring 348 in the position in which it is shown in the drawings, in which position the port 335 is uncovered by the slide valve 338.

The control reservoir I9 is connected by means of a pipe 345 to the pipe 258 at a point intermediate the fluid pressure operated valve device I6 and the application magnet valve device II.

In the installation of a system of this type on a train the engineers brake valve I, the conductors brake valve 2, the fluid pressure operated valve device 3, the main reservoir 4, the relay valve device 5, and the fluid pressure operated switch device 1 are mounted on the engine, while each of the cars of the train is provided with a relay valve device 9, an application magnet valve device II, a release magnet valve device I2, a brake cylinder I4, a supply reservoir I5, a fluid pressure operated valve device I6, and a control reservoir IS. The control pipe I1 and the brake pipe I8 are extended throughout the entire length of the train, the connections between the cars being made by means of flexible couplings. A conductors brake valve 2 may also be installed on each of the cars in the train. In addition the wires I11 and I19 are carried throughout the length of the train.

In the operation of the system, assuming that the main reservoir 4 charged with fluid under pressure, and that the operating handle 42 of the engineers brake valve I is turned to the release position, fluid will flow from the main reservoir by way of the pipe and passage 40 to the chamber 39 in the engineers brake valve, and therefrom by way of a passage in the rotary valve 31 to the port 3| and the brake pipe I8. If desired the pressure of the fluid supplied from the main reservoir may be reduced by means of a feed valve not shown. The fluid which flows to the brake pipe I3 flows therethrough to the relay valve device 9, and the fluid which is supplied to the passage 230 in the relay valve device 9 unseats the check valve element 225 so that fluid flows to the chamber 221 in the check valve 228, and therefrom by way of the passage 223 to the supply reservoir I5 charging this reservoir with fluid under pressure.

Fluid which is supplied to the brake pipe I8 also flows therefrom by way of the pipe 326 to the chamber 324 in the fluid pressure operated valve device It and forces the piston 322 to the right as viewed in Fig. 1 of the drawings, if it is not already in this position. This causes the slide valve 330 to uncover the port 335 in the valve seat 33! to permit fluid to flow from the pipe 2I5 by way of the pipe 338 to the valve chamber 328, and therefrom by way of the port 335 and the pipe 345 to the control reservoir I8 charging this reservoir with fluid under pressure.

Fluid which is supplied from the valve device I6 to the pipe 258 also flows to the chamber 250 in the-application magnet valve device I I, and from this chamber fluid flows by way of passage 2' to the chamber 265, and therefrom past the double beat valve 266 to the chamber 265 from which the fluid flows by way of the passage 213 to the chamber 251 on the spring side of the valve 252.

The fluid which is supplied to the brake pipe I8 also flows by way of the pipe 69 to the chamber 66 in the fluid pressure operated valve device 3, while fluid under pressure from the main reservoir 4' flows by way of the pipe 12 to the valve chamber 10 on the opposite side of the piston 65 of the valve device 3, and, as the pressures on opposite sides of the piston 65 are substantially equal, the piston 65 will be moved to the position in which it is shown in the drawings by means of the spring 88, in which position the slide valve 14 cuts ofi communication through the port 64 and establishes communication between the ports 19 and 80. Fluid also flows from the main reservoir 4 by way of the pipe I38 to the chamber H0 in the relay valve device 5.

Fluid supplied to the brake pipe I8 also flows by way of the pipe 48 to the chamber 46 in the conductors brake valve 2.

When it is desired to effect an application of the brakes the operating handle 42 of the engineers brake valve I is turned to the service position, in which position communication is maintained between the chamber 39, which is connected to the main reservoir, and the brake pipe I8, as is clearly shown in Fig. 2 of the drawings, which is a diagrammatic view of the ports in the engineers brake valve.

When the operating handle 42 is turned to the service position a communication is established between the chamber 39 and the port 35, which has the pipe 36 connected thereto, the communication being by way of a choke or restricted portion 38 to limit the rate of flow of fluid from the main reservoir to the pipe 36.

Fluid which is supplied to the pipe 38 flows therethrough to the port 19 in the fluid pressure operated valve device 3 and therefrom by way of the cavity 11 in the slide valve 14 to the port 88, and thence by way of the pipe 32 to the passage 65 in the relay valve device 5.

Fluid which is supplied to the passage flows therefrom to the passage I61 in the fluid pressure operated switch device 1, and thence to the chamber I65 where it forces the diaphragm I63 downwardly and thus moves the stem I18 out of engagement with the contact I15, thereby interrupting the circuit to the winding of the release magnet valve I2, and into engagement with the contact I18.

When the winding of the release magnet valve is deenergized, the valve 296 is moved to the upper seated position by the spring 385, so as to cut off communication between the chamber 295 and the atmosphere, and to establish communication between the chamber 299 and the chamber 295.

When the stem I18 engages the contact I16 a circuit is established through the winding of the application magnet valve device II and on energization of this winding the double beat valve element 266 is forced downwardly against the spring 255 so as to cut on: communication between the chamber 253 and the chamber 265, and to establish communication between the chamber 265 and the atmosphere by way of the chamber 268. This errnits fluid to escape from the chamber 251 on the upper side of the valve element 252 to the atmosphere, and on the release of fluid from the chamber 25?, the fluid in the chamber 256 acting on the portion of the valve element 252 out wardly oi the seat rib 253 forces this valve element upwardly so as to permit fluid to flow from the chamber 258 to the chamber 268, and therefrom through the restricted passage 262 and the passage 26! to the control pipe I1, and to the passage I89 in the relay valve device 9 which leads to the chamber I83.

Fluid supplied to the control pipe I1 by the application magnet valve device II, or by any other source, flows by way of the passage 28l t the chamber 280 in the release magnet valve device l2 and from this chamber fluid flows by Way of the passage 38! to the chamber 299 from which fluid may flow past the double beat valve 383 to the chamber 295, and therefrom by way of the passage 298 to the chamber 28'l on the spring side of the valve 282, where it acts upon the valve 282 to maintain it in engagement with the seat rib 284.

The application magnet valve device I l supplies fluid from the control reservoir l9, which will be recharged from the supply reservoir G which is maintained charged with fluid under pressure by flow from the brake pipe past the check valve 225, while the control reservoir is also charged from the brake pipe l8, assuming that the pressure of the fluid in the brake pipe has been maintained so that the slide valve 330 of the fluid pressure operated valve device It is maintained in a position to permit communication through the port 335 therein.

The fluid which is supplied to the passage 95 in the relay valve device 5 also flows by way of this passage and the restricted portion 9 3 to the chamber 93 on the left hand side of the piston 92, and forces this piston to the right as viewed in Fig. l of the drawings and after a certain amount of movement of the piston 92 the stem H36 engages the end of the slide valve lflll, and moves it to the right so as to cut oil communication through the ports Hi2 and M3 in the slide valve seat lfll.

On further movement of the piston 92 the end of the stem it engages the end of the stem 525 of the pilot valve element 529 so as to move this valve element away from the seat rib l22 against the spring 524. This permits fluid to flow from the chamber l iii to the valve chamber 93 at a slow rate so as to permit the pressures in these chambers to approach equalization and thus reduce the force exerted by the fluid in the chamber 5 it acting on the valve element l l l, and tending to hold the valve element against the seat rib On further movement of the piston 92 the stem will engage the member H6 and the valve 5 5 i will be forced away from the seat H2 against the spring lit, and fluid will thereupon flow at a more rapid rate from the chamber Hi3, which is connected to the main reservoir 4, to the valve chamber Q2, which is connected by way of the passage i352 to the control pipe IT.

The fluid which is supplied to the passage 95 also flows by way of the passage M5 to the chamber on the lower side of the valve element M2 of the check valve device 536, and, on a predetermined increase in the pressure of the fluid in the passage 95, the valve element M2 will be moved away from the seat rib Hi l against the spring t ll, and fluid will thereupon flow from the passage to the chamber l lil, which is connected by of the passage M8 to the passage !32 which leads to the control pipe ll.

it will be seen, therefore, that on movemen of the handle 52 of the engineers brake valve l to the service position fluid may be supplied to the control pipe from a plurality of sources, one of these being by way of the application magnet valve device El, another being by operation of relay valve device 5, and another being by the supply or fluid to the passage 532 directly from engineers brake valve by way of the pipe 82 and the passage 95.

On an increase in the pressure of the fluid in the control pipe I! the pressure of the fluid in the chamber H88 in the relay valve device 9 will be increased, and the piston I86 will be forced downwardly so that the end of the stem ills engages the stem 2 l2 of the pilot valve 266, causing the pilot valve 266 to be forced away from the seat rib 288 against the spring 299, while the slide valve W2 will be moved to a position to cut ofi communication to the passage H95.

Thereupon fluid will flow at a slow rate from the valve chamber I93, which is constantly connected to the supply reservoir l5 by way of the passage and pipe 235, to the slide valve chamber tall, which is connected to the brake cylinder M by way of the and passage 2E8.

When the pilot valve 286 is unseated the pressures in the valve chamber l9! and the slide valve chamber lei will tend to equalize, thus reducing the force exerted by the fluid under pressure in the chamber 191 and tending to hold the valve 999 against the seat rib Elli. Thereafter on further movement of the piston l 86 downwardly the valve I99 will be moved away from the seat rib 26! against the spring 202, and fluid will flow from the valve chamber l9? to the slide valve chamber lei, and therefrom to the brake cylinder at a more rapid rate.

On an increase in the pressure of the fluid in the control pipe i! there will be a similar increase in the pressure of the fluid in the chamber I68 of the fluid pressure operated switch device I, which is connected to the control pipe I! by way of the passage I69, and when this pressure increases to a value substantially equal to that in the chamber H65 the diaphragm I63 will be moved upwardly so as to move the stem I'm to the lap position, in which position the stem is out of engagement with the contact H8 and the contact I75, so that the circuits to the windings of both the application magnet valve device II and the release magnet valve device l2 are interrupted. This cuts oh the further supply of fluid to the control pipe I! by the application magnet valve device ll.

Similarly, assuming that the handle 42 of the engineers brake valve has been moved from the service position to the lap position, which results in the cutting 01? of the flow of fluid from the main reservoir to the pipe 35 and therefrom to the passage 95, the supply of fluid to the chamber 93 will be cut off, and, as soon as the pressure in the valve chamber 98 increases to a value substantially equal to that in the chamber 93, the piston 92 will be moved to the left and the stern IE6 will move the slide valve it to the lap position, while the stem we will be moved out of engagement with the member l 16 and the stem l 25 of the pilot valve I20 so as to permit the valve H l and the pilot valve 20 to seat and cut oil the supply of fluid to the valve chamber 98 and thereby to the passage I32 from the main reservoir.

Likewise, when the supply of fluid under pressure to the pipe 35 is cut off the supply of fluid to the passage 95 will be cut off and the fluid can no longer flow from the passage 95 past the check valve M2 to the passage 132.

It will be seen, therefore, that when the handle 42 of the engineers brake valve I is turned to the lap position after having been moved to the service position, the relay valve device 5 will operate to cut off the supply of fluid under pressure to the control pipe by way of the relay valve device as soon as the pressure in the control pipe I! increases to a value substantially equal to that establishedby operation of the engineers brake valve I in the pipe 82 leading to the relay valve device. Likewise the fluid pressure operated switch device I will operate to cut oif the supply of fluid to the control pipe II by operation of the application magnet valve device I I as soon as the pressure of the fluid in the control pipe IT increases to a value substantially equal to that supplied to the fluid pressure operated switch device by operation of the engineers brake valve I.

The relay valve device 9 will operate to supply fluid under pressure to the brake cylinder I4 until the pressure of the fluid established in the brake cylinder and in the valve chamber I9I is substantially equal to that in the chamber I88 on the opposite side of the relay valve device piston I88, whereupon the piston I86 will be moved upwardly to the lap position, in which position the stem I94 is moved out of engagement with the member 294 and the stem 2I2 associated with the pilot valve 206, while the slide valve I92 laps the exhaust port I95.

This cuts off the further supply of fluid under pressure to the brake cylinder I4 and maintains the pressure of the fluid previously supplied to the brake cylinders.

If it is desired to increase the degree of application of the brakes the handle 42 of the engineers brake valve I is again turned to the service position so as to again supply fluid under pressure to the pipe 36 and therefrom to the pipe 82 which leads to the passage 95 in the relay valve device 5, thereby increasing the pressure of the fluid in the chamber I65 of the fluid pressure operated switch device I, thus causing the diaphragm I63 to move downwardly so as to move the stem IIII into engagement with the contact I18 and establish a circuit through the winding of the application valve device II so as to cause this magnet valve device to again supply fluid from the reservoir I9 to the control pipe H.

In addition the pressure of the fluid in the chamber 93 of the relay valve device 5 will be increased, and this valve will be caused to operate to supply fluid to the control pipe IT.

The increase in the pressure of the fluid in the control pipe I! results in an increase in the pressure of the fluid in the chamber I89 of the relay valve device 9, and causes this valve device to again operate to supply fluid under pressure to the brake cylinder I4.

When the desired degree of brake application has been secured the operating handle 42 of the engineer's brake valve is returned to the lap position so as to cut off the supply of fluid under pressure to the chamber 93 of the relay valve device 5, and to the chamber I65 of the fluid pressure operated switch device I, and when the pressure of the fluid in the control pipe I! increases to a sufiicient value the relay valve device 5 and the fluid pressure operated switch device I will again move to their lap positions.

If it is desired to eifect an emergency application of the brakes the handle 42 of the engineers brake valve is turned to the emergency position, in which position the ports in the rotary valve 3! establish communication between the chamber 39 and the port 35, which has the passage and pipe 36 connected thereto, this communication not having a choke therein as does the port through which communication between these points is established in the service position of the engineers brake valve.

In addition, when the handle 42 is turned to the emergency position, the rotary valve 31 cuts off communication between the chamber 39 and the port 3! leading to the brake pipe, and the ports in the rotary valve 31 establish communication between the port 3| and the atmospheric exhaust port 33 so as to release fluid from the brake pipe I8.

Upon a reduction in the pressure of the fluid in the brake pipe I8 there will be a similar reduction in the pressure of the fluid in the chamber 66 of the fluid pressure operated valve device 3, and the piston 55, being subject on the opposite side to main reservoir pressure in the valve chamber ID, will be moved to the left, as viewed in Fig. 1 of the drawings, against the spring 88, and the stem 8? will move the slide valve 7 3 on the valve seat I5 so that the cavity I? in the slide valve no longer establishes communication between the ports I9 and 88, and so that the end of the slide valve I4 uncovers the port 84, with the result that fluid under pressure will flow from the main reservoir by way of the pipe '52 to the. valve chamber I0, and therefrom through the restricted passage and the port 84 to the pipe 82 leading to the relay valve device 5.

During the time interval after the handle 42 of the engineers brake valve has been moved to the emergency position, and before the piston 55 is moved to the left as viewed in Fig. 1 of the drawings, fluid under pressure will flow through the engineers brake valve I to the pipe 35 and therefrom to the port I9 and the cavity TI to the passage 89 and therethrough to the pipe 82, but on movement of the piston 65 as the result of the reduction in the pressure of the fluid in the brake pipe, the supply of fluid to the pipe 82 from the pipe 96 will be cut oif and fluid will thereafter be supplied to the pipe 82 from the valve chamber III.

The rate of flow of fluid to the pipe 82 and therefrom to the chamber 93 in the relay valve device 5 and the chamber I65 in the fluid pressure operated switch device I is somewhat more rapid through the choke 89 than through the port in the rotary valve 37 through which fluid is supplied to the pipe 82 when the engineers brake valve I is in the service position. This results in a more rapid increase in the pressure of the fluid in the relay valve device 5, and in the fluid pressure operated switch device I, than occurs during a service application of the brakes, so that these devices are very quickly conditioned to increase the pressure of the fluid in the control pipe I I and thus effect an application of the brakes.

An emergency application of the brakes may also be effected by means of the conductors brake valve 2 by turning the lever 58 which causes the cam surface 59 to press upon the end of the lever 51, thereby forcing the stem 55 downwardly and moving the valve 59 away from the seat rib 5!, thus permitting fluid to escape from the brake pipe I8 by way of the pipe 48.

The consequent reduction in the pressure of the fluid in the brake pipe I8, which will take place even though the engineers brake valve I is in the release or lap position, in which position fluid is supplied to brake pipe at a rate less rapid than the rate at which fluid is vented from the brake pipe It by means of the conductors brake valve, causes the piston 65 of the fluid pressure operated valve device 3 to be moved to the emergency position and conditions the valve device 3 to supply under pressure to the pipe 82 to effect an application of the brakes.

In order to eifect a release of the brakes after an application the handle 42 of the engineers brake valve l is turned to the release position, in which position a port in the rotary valve 3'! establishes a communication between the cham ber 39 and the brake pipe 18 so as to re-establish the pressure of the fluid in the brake pipe if there has been a reduction in the pressure in the brake pipe, and at the same time the ports in the rotary valve 3'! establish communication between the port 35, leading from the pipe 38, and the atmospheric exhaust port 33.

When the port 35 is connected to the atmospheric exhaust port 33 fluid under pressure is permitted to flow from the pipe 36 to the atmosphere, and as the pipe St is in communication with the pipe 82 and the passage 95 of the relay valve device 5 by way of the cavity '1'! in the slide valve it of the fluid pressure operated valve device 3, fluid will flow from the passage 95 to the atmosphere.

If at the time the engineers brake valve 5 is turned to the release position the slide valve it is not in the position in which the cavity ll establishes communication between the ports 19 and 88, it will be moved to this position as soon as the pressure of the fluid in the brake pipe i8 is re-established.

Upon the release of fluid under pressure from the passage 95 fluid will be released from the chamber I55 in the fluid pressure operated switch device 1, and, on a reduction in the pressure of the fluid in the chamber !65, the diaphragm 183 will be moved upwardly by the pressure of the fluid in the chamber 583 on the lower side thereof, and the stem He will be moved into engagement with contact H5, thereby establishing a circuit through the wire Ill which leads to the winding of the release magnet valve device l2.

Upon energization of the winding of the release magnet valve device l2, the double beat valve element 2% associated with the valve device is moved downwardly to cut off communication between the chamber 295 and the chamber 299, and to permit communication between the chamber 295 and chamber 353 which is connected to the atmosphere. This permits fluid to flow from the chamber 28? on the upper side of the valve 282 to the chamber 285 by way of the passage 288, and therefrom to the atmosphere.

On the consequent reduction in the pressure of the fluid in the chamber 23? the pressure of the fluid in the chamber Adi! acting on the portion of the valve 232 outwardly of the seat rib 23 i forces the valve 282 upwardly against the spring 285, and away from the seat rib 284, to permit fluid to flow from the chamber 285 to the chamber 293, and therefrom to the atmosphere by way of the passage 251?: having the choke 293 interposed therein.

The chamber 289 is connected to the control pipe ll by way of the passage Eti so that on the release of fluid from the chamber 23% fluid will be released from the control pipe ll.

On the release of fluid under pressure from the passage $5 of the relay valve device fluid will also be vented from the chamber 23 and the ,iston (-32 will be moved to the left so that the stem let moves the slide valve N39 to the position in which it is shown in Fig. l of the drawings, in which position communication is established by way of the port it? through the slide valve i539 with the port Hi2 in the slide valve seat and between the valve chamber 58 and the port m3,

so that fluid is released from the slide valve chamber to the atmosphere, while the valve ele ment l I and the pilot valve Hill are permitted to move to their seats, if they are not already in engagement therewith.

Upon the release of fluid under pressure from the valve chamber 98 fluid is released from the passage 32 and from the control pipe ll.

In addition, on the reduction in the pressure of the fluid in the passage 95 to a predetermined amount below the pressure of the fluid in the passage I32, which communicates with the control pipe 57, the fluid in the passage I53 will move the check valve l5! against the spring I55 away from the seat rib it? so that fluid may flow from the passage 532 to the chamber I50 and therefrom by way of the passage I56 to the passage 95, from which it is released to the atmosphere.

If the handle of the engineers brake valve I is left in the release position all of the fluid in the pipe 36, and in the passage 95, will be vented to the atmosphere so that substantially no fluid under pressure will be present in the chamber I65 of the switch device 7, or in the chamber 83 of the relay valve device 5.

The pressure of the fluid in the control pipe I! will continue to reduce until it is reduced to a value substantially equal to that in the chamber 93 of the relay valve device '5 and the chamber 565 of the switch device l. When the pressure of the fluid in the chamber M58 is reduced to a value substantially equal to that in the chamber i655 on the opposite side of the diaphragm 563, the diaphragm is held in the position in which the stem lli! is out of engagement with the contact H8, and is in engagement with the contact H5, thereby continuing to interrupt the circuit to the winding of the application magnet valve device I! and maintaining the circuit through the winding of the release magnet valve device 12. The control pipe, therefore, will be connected to the atmosphere by way of the valve chamber es and the ports m2 and W3, and by way of the release magnet valve device i2.

On the release or" fluid under pressure from the control pipe ll fluid will be released from the chamber IE8 on the upper side of the piston ltli of the relay valve device 9, and this piston will thereupon be moved upwardly by the pressure of the fluid in the slide valve chamber l 9? on the lower side of the piston it'd, thus causing the slide valve !92 to be moved to a position to un cover the exhaust passage 95 to permit fluid to escape from the brake cylinder to the atmosphere by way of the passage I95, the slide valve chamber IQI, and the pipe andpassage 2E5. This effects a release of the brakes.

In the braking system provided by this invention means is provided which is responsive to the pressure of the fluid in the brake pipe 83 and which operates on a reduction in the pressure of the fluid in this pipe to cut off communication between the supply reservoir !5, from which fluid is supplied to the brake cylinders, and the application magnet valve devices by means of which fluid is supplied to the control pipe.

If, therefore, the pressure of the fluid in the brake pipe i8 is reduced by reason of a break in two of the train, which would be accompanied also by a rupture of. the control pipe El, the supply oi fluid from the supply reservoirs i5, which is the source of fluid for applying the brakes, to the application magnet valves will be cut oif, with the result that the application magnet valves H cannot continue to supply fluid to the control pipe and thereby deplete the supply of fluid in the supply reservoirs l5.

On a reduction in the pressure of the fluid in the brake pipe 18 the piston 322 of the fluid pressure operated valve device is shifted to the left as viewed in the drawings, so that the slide valve 330 cuts off communication through the passage 335. The application magnet valve ii therefore, cannot supply fluid from the supply reservoir 15, but it may supply fluid to the control pipe from the control reservoir 19, which provides a supply of fluid suflicient to effect an application of the brakes if the control pipe i1 remains intact. Therefore, after an emergency application of the brakes, which is accompanied by a reduction in the pressure of the fluid in the brake pipe l8, the application magnet valve device will normally operate to supply fluid to the relay valve device and to the control pipe to effect an application of the brakes.

In Fig. 3 of the drawings I have illustrated a modified form of the braking system embodying my invention. The system illustrated in this figure of the drawings is generally similar to that shown in Fig. 1 of the drawings, and identical reference characters are employed for the elements of the system which are identical with the elements employed in the system shown in Fig. l.

The system shown in this figure of the drawings differs from that shown in Fig. 1 of the drawings, however, in that the application magnet valve device If supplies fluid directly from the supply reservoir 15 rather than from a control reservoir, or indirectly from the supply reservoir 15 through a fluid pressure operated valve device such as is employed in the system shown in Fig. l of the drawings.

The connection between the application magnet valve device 11 and the supply reservoir 15 is effected by way of the passage 358 which joins the passage 215 leading to the supply reservoir 15.

In the system shown in this figure of the drawings a fluid pressure operated switch device, indicated generally by the reference numeral 369, is employed and is mounted on the engine of the train. The switch device 360 comprises a casing constructed of a plurality of sections, and including the sections 36l, 362, 393 and 364.

A diaphragm 365 is clamped between the easing sections 361 and 362, and has on one side thereof a chamber 361, which is connected to the atmosphere by way of a passage 369, and has on the other side thereof a chamber 319 which is connected to a reservoir 315 by way of a pipe 316, while the reservoir 315 is connected to the brake pipe 18 by Way of a pipe 318 having a choke or restricted portion 319 interposed therein. A diaphragm 382 is clamped between the casing sections 362 and 353, this diaphragm being of somewhat smaller diameter than the diaphragm 365. The diaphragm 382 is subject on one side to the pressure of the fluid in the chamber 319, and is subject on the other side to the pressure of the fluid in a chamber 383.

The casing section 364 has a chamber'386 formed therein and connected to the portion of the control pipe l1 which leads from the relay valve device 5, and in addition has a chamber 388 formed therein inwardly of a seat rib 399, and which is connected to the portion of the control pipe 11 which leads to the relay Valve device 9.

A diaphragm 393 is clamped between the easing sections 393 and 364, and is adapted to be urged into engagement with the'seat rib 399 by means of a plunger 395, which is actuated by a stem 391, which is operatively secured to the diaphragms 365 and 332, and by means of a spring 398 which extends between a shoulder 399 on the casing section 353, and the plunger 395 and normally urges the plunger downwardly so as to press the diaphragm 393 against the seat rib 399.

The chamber 383 is connected by way of a passage 492 with the portion of the control pipe 11 which is connected to the chamber 388.

The stem 391 has secured thereto, but insulated therefrom, a contact 495 which is adapted to establish a circuit between stationary contacts 453 and 491 to which the portions of the wire i183 which lead from the fluid pressure operated switch device 1, and to the application magnet valve devices H are connected.

In the operation of this system, when the brake pipe 18 is at atmospheric pressure the chamber 319 will also be at atmospheric pressure, and the plunger 395 will be urged downwardly by the spring 333 so as to cause the diaphragm 393 to engage the seat rib 399 and thereby cut off communication through the control pipe 11. In this position of the device the stem 391 will maintain the contact 495 out of engagement with the contacts 455 and 491, thus interrupting the circuit to the windings of the application magnet valve devices and maintaining these devices deenergized so that no fluid under pressure will be supplied thereby to the control pipe 11.

On an increase in the pressure of the fluid in the brake pipe 18 fluid will flow therefrom by Way of the pipe 313 and a restricted portion 319 to the reservoir 315 and to the chamber 310 intermediate the diaphragms 355 and 382, and because of the differential areas of these diaphragms, the pressure of the fluid in the chamber 319 will force the stem 391 upwardly so that the contact 595 is in engagement with the contacts 496 and 491 and a circuit will be completed from the fluid pressure operated switch device 1 to the application magnet valve devices H.

In addition, the plunger 395 will be lifted away from the diaphragm 393 so that fluid under pressure in the control pipe 11 acting on the lower face of this diaphragm will lift the diaphragm away from the seat rib 395 and permit communication between the different portions of the control pipe l1.

If, during the operation of the system the pressure of the fluid in the brake pipe 18 is reduced, either intentionally as a result of an emergency application of the brakes, or unintentionally as the result of a breakage of the brake pipe 18 caused by a breaking in two of the train or by any other reason, fluid will flow from the reservoir 315 to the brake pipe l8 through the restricted portion 319, and after a time interval, the pressure of the fluid in the reservoir 315 and in the chamber 319, which is connected thereto, will be reduced, and the force exerted by the fluid under pressure in the chamber 318 will be insufficient to maintain the stem 391 in its upper position and it will be moved to its lower position by the spring 398. This will cause the contact 495 to be moved away from the contacts 496 and 491 to interrupt the circuit to the application magnet valve devices H, and will cause the diaphragm 393 to be moved against the seat rib 399 to cut off communication through the control pipe 11.

Fluid will flow from the reservoir 315 to the brake pipe at a relatively slow rate because of the restricted capacity of the choke 319 so that the pressure of the fluid in the reservoir 315, and in the chamber 370, will be maintained for a period so as to maintain the contact 405 in engagement with the contacts 406 and for a time interval after the reduction in the pressure of the fluid in the brake pipe I8 occurs. This time interval is long enough to permit the application magnet valve devices II to supply suflicient fluid under pressure to the control pipe I! to eifect an application of the brakes, providing the control pipe I! has not been broken.

After the lapse of this time interval, the pressure of the fluid in the reservoir 375 and in the chamber 370 will be reduced so that the plunger 39'! will be moved downwardly and the circuit through the Winding of the application magnet valve devices will be interrupted, thereby cutting off the further supply of fluid to the control pipe I! by way of the application magnet valve devices. This prevents the further release of fluid under pressure from the supply reservoir l5, and prevents a continued supply of fluid under pressure to the control pipe II, which would result in a complete release of the fluid in the supply reservoirs H5 in the event that the control pipe I! were broken.

In the system shown in Fig. 3 of the drawings, therefore, it will be seen that the fluid pressure operated switch 36%! operates on a reduction in the pressure of the fluid in the brake pipe l8 to interrupt the circuit to the windings of the application magnet valve devices so that the supply of fluid from the supply reservoirs I5 to the control pipe will be cut ofl, thereby preventing the complete loss of fluid from the supply reservoirs l5.

It will be seen also that in each of the systems P shown in this application means is provided which is responsive to the pressure of the fluid in the brake pipe, and which operates on a reduction in this pressure to control the electrically operated means for supplying fluid to the control pipe so as to cut off the supply of fluid thereto from the supply reservoirs, that is, from the reservoirs from which fluid is supplied to the brake cylinders in effecting an application of the brakes.

While a preferred form, and a modified form of the braking system embodying my invention have been illustrated and described in detail, it should be understood that the invention is not limited to these details of construction and that numerous changes and modifications may be made without departing from the scope of the following claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a fluid pressure brake, in combination, a brake cylinder, a supply reservoir, a control reservoir, a relay valve device operated by an increase in fluid pressure for supplying fluid under pressure from the supply reservoir to the brake cylinder, means for supplying fluid under pressure to the control reservoir from the supply reservoir, a brake pipe, means subject to and operated upon a reduction in the brake pipe pressure for cutting ofi the supply of fluid to the control reservoir from the supply reservoir, and means for supplying fluid under pressure to the relay valve device from the control reservoir.

2. In a fluid pressure brake, in combination, a control pipe, a supply reservoir, a brake cylinder, a relay valve device operated by an increase in the pressure of the fluid in the control pipe for supplying fluid under pressure to the brake cylinder from the supply reservoir, manually controlled valve means for supplying fluid under pressure to the control pipe at one point, electrically controlled means for supplying fluid under pressure to the control pipe from the supply reservoir at another point, a brake pipe, and valve means subject to and operated upon a reduction in the pressure of the fluid in the brake pipe for cutting ofl communication between the supply reservoir and the point on the control pipe at which fluid is supplied thereto by the manually controlled valve means.

3. In a fluid pressure brake, in combination, a brake cylinder, a supply reservoir, a control reservoir, means for supplying fluid to the control reservoir from the supply reservoir, a brake pipe, a control pipe, a relay valve device operated by an increase in fluid pressure in the control pipe for supplying fluid under pressure to the brake cylinder from; the supply reservoir, manually controlled valve means for supplying fluid under pressure to the control pipe, electrically operated means for supplying fluid under pressure to the control pipe from the control reservoir, and means subject to and operated upon a reduction in the pressure of the fluid in the brake pipe for cutting off the supply of fluid from the supply reservoir to the control reservoir.

4. In a fluid pressure brake, in combination, a brake pipe, a brake cylinder, a relay valve device operated on an increase in fluid pressure for supplying fluid under pressure to the brake cylinder, electrically operated means for supplying fluid under pressure to the relay valve device, and means for controlling the supply of current to the electrically operated means, said means comprising an abutment subject to the pressure of fluid in a chamber connected to the brake pipe, means controlled by said abutment and operated on a reduction in the pressure in said chamber for cutting off the supply of current to the electrically operated means, and means to restrict the rate of flow or fluid from the chamber to the brake pipe, whereby the pressure of the fluid in said chamber is maintained for a time interval subsequent to a reduction in the pressure of the fluid in the brake pipe.

5. In a fluid pressure brake, in combination, a brake cylinder, a. supply reservoir, a control reservoir, a relay valve device operated by an increase in fluid pressure for supplying fluid under pressure to the brake cylinder, means operative to supply fluid under pressure from the control reservoir to operate said relay valve device, means subject to brake pipe pressure for controlling the supply of fluid under pressure from the supply reservoir to the control reservoir and operated upon a reduction in brake pipe pressure to cut ofl the supply of fluid from the supply reservoir to the control reservoir.

ELLIS E. HEWITT. 

